1. Field of the Invention
The invention relates to a data adapter for communication devices for the telecommunication of useful data, particularly of packet data and/or voice data, having: (a) a data interface supporting a link to a communication device; (b) a data transmitter for wireless transmission and reception of data based on a prescribed air interface protocol; and (c) a controller which is connected to the data interface and to the data transmitter, the data adapter further comprising program modules, the controller and program modules being configured for two-way transmission of the useful data using the data interface on the basis of an appropriate interface protocol and using the data transmitter based on the prescribed air interface protocol.
2. Description of the Related Art
For the telecommunication of useful data—transmitting and receiving, for example, voice data and/or packet data over relatively long distances—between physically separate data terminals (communication devices) in the form of data sources and data sinks in a telecommunication network (the scenario for the telecommunication of useful data), special data adapters are used which link the data terminals to the telecommunication network such that the useful data can be transmitted on the network-specific transmission link.
The publication “it+ti—Informationstechnik und technische Informatik [Information Technology and Information Systems]” 37 (February 1995), No. 1, R. Oldenbourg Verlag [publishers], pages 21 to 28, presents, under the heading “Mobile Computing—Komponenten, Systemintegration, Anwendungen [Mobile Computing—Components, System Integration, Applications]”, a scenario for the telecommunication of useful data, particularly packet data.
For the telecommunication of useful data, particularly packet data, the data adapters used to date for communication devices, for example, in the form of personal computers, notebook computers, and PDA (Personal Digital Assistant), units have primarily been modems and PCMCIA cards (Personal Computer Memory Card International Association).
While the modems can be used to link the aforementioned communication devices essentially to line-connected telecommunication networks, the PCMCIA cards can also be used to link the devices to wireless telecommunication networks. Thus, a PCMCIA card and a GSM handset (GSM mobile phone) can be used to link a Notebook to the GSM network in a known manner, for example. Although such an equipment arrangement can be used independently of location, it cannot be used for different user-specific application instances. Thus, for example, it is not possible for a dedicated user-specific network for the telecommunication of useful data to be installed by the user independently of the telecommunication network.
The publication “Vortrag von A. Elberse, M. Barry, G. Fleming zum Thema: “DECT Data Services—DECT in Fixed and Mobile Networks”, 17./18. Jun. 1996, Hotel Sofitel, Paris; Seiten 1 bis 12 and Zusammenfassung [Presentation by A. Elberse, M. Barry, G. Fleming on: “DECT Data Services—DECT in Fixed and Mobile Networks”, Jun. 17/18, 1996, Hotel Sofitel, Paris; pages 1 to 12 and abstract]” illustrates—on the basis of the publication “Nachrichtentechnik Elektronik [Telecommunications Electronics]” 42 (1992) January/February No. 1, Berlin, DE; U. Pilger “Struktur des DECT—Standards [Structure of the DECT Standard]”, pages 23 to 29 in conjunction with ETSI publication ETS 300175-1 . . . 9, October 1992 and the publications Components 31 (1993), No. 6, pages 215 to 218; S. Althammer, D. Brückmann: “Hochoptimierte IC's für DECT—Schnurlostelefone [Ideal ICs for DECT Cordless Telephones]” and WO 96/38991 (cf. FIGS. 5 and 6 with the associated description for each]—the basic use of DECT technology (Digital Enhanced Cordless Telecommunication) for wireless mobile telecommunication of voice data and/or packet data, where DECT network access technology for the telecommunication of useful data enables the user both to become his own network operator and to have the option of accessing a superordinate telecommunication network.
Furthermore, German Patent DE-40 26 426 discloses a system for data transmission in which one or more personal computers and peripherals, particularly printers, can be connected to one another within a space wirelessly, specifically with selective access over the radio path for the purposes of data transmission.
In addition, German Patent DE-43 20 047 discloses a cordless telephone which, to extend its use to any other desired applications, has at least one mobile part which is supplemented by means of an additional interface, which is inverse to the network, to form a cordless telephone line unit (telephone outlet). Such an access capability enables virtually all the usual terminals, such as telephones, videotex, modem, fax, answering machine, telecommanding and teleaction devices and ancillary devices, to be operated directly on a mobile and wireless basis.